Dosing device, in particular for powder

ABSTRACT

This dosing device ( 1 ) comprises a container ( 2 ) and a plug ( 4 ) comprising, in addition to a part ( 15 ) for connection to the container, two mobile outer parts ( 16  and  17 ). One of the mobile parts ( 16 ) is held in place during dosing, while the container ( 2 ) rotates continually to assist the flow of the content of same; the other outer part ( 17 ) can be rotated as necessary to adjust the opening of the plug. The movements can be carried out by a machine on which the dosing device is positioned upside down, with the plug facing downwards.

The present invention relates to a dosing device, in particular for powder, and the usefulness thereof is more particularly evident for hazardous products, the dissemination of which must be avoided and which often have to be handled from the outside of an enclosure in which they are confined, such as a glove box, a shielded casing or a shielded cell.

The usual method of dosing consists in progressively pouring out the desired amount of the product, contained firstly in a recipient or a container, into another recipient generally positioned on a balance, in order to be able to stop as soon as the desired amount has been reached. A funnel is often arranged on the second recipient to aid the decanting. This method of dosing is employed for all products to be dosed, including those that have been indicated above and which must be confined in a protective enclosure, the handling then taking place either through the intermediary of a glove fixed to the enclosure and traversing it, or by a remote handling device. It is however obvious that it presents risks of accidents or dosing errors stemming from incorrect tiltings of the original container of the product, too late stoppages of the decanting, or disseminations of the product via accidental projections or by remanence on the funnel. These risks are greater when the powders are compact or sticky, which reduces their ability to flow, whereas the expedients that may be envisaged, such as shaking the container or tapping on it, have an unpredictable efficiency and can also lead to a too sudden acceleration of the flow; or when the containers are heavy; or when the dosing is carried out by a remote handling device or through a glove, thus with reduced address or less good visibility.

Mechanical dosing devices also exist where handling of the original container of the product and the associated vagaries and risks are reduced. The document U.S. Pat. No. 4,836,417 may be cited, in which the powder is poured into a hopper comprising a lower distribution neck. The hopper is positioned on a diaphragm which the neck traverses, and this diaphragm is provided with piezoelectric vibration generators. The vibrations communicated to the diaphragm are transmitted to the mouth so as to shake the powder and to assist the flow of same via the mouth. This device nevertheless does not make it possible to control easily the characteristics of the flow and particularly its flow rate, and it is all the same necessary to take precautions against the dissemination of the product, the neck remaining continually open.

Another document describing a dosing device is WO-A-2008/071 872. The original container of the product comprises a plug at its opening; this plug is provided with an orifice and a mobile mechanism to completely close or open the orifice as necessary and, here again, to vary the flow characteristics. More complicated, but automatable, handling operations are still nevertheless necessary to act on this mechanism for opening the plug, which reduces the interest of this device for uses in a confined enclosure; it has rather been designed for the pharmaceutical industry.

The subject matter of the invention is a dosing device of a different type, remarkable in that it avoids disseminations of products, makes it possible to adjust relatively easily the flow rate, and in that it can be easily and without risk handled remotely, even by rudimentary mechanical means.

In a general form, the invention relates to a dosing device comprising a container having an opening, a plug arranged at the opening of the container and a first orifice and having a mobile mechanism on the first orifice of the plug to open or to close as necessary the plug and thus the dosing device; characterised in that the plug comprises: a first outer part, arranged around a connection to the container, the connection being positioned at the opening of the container, so as to be able to rotate around said connection and further comprising a sealing part also arranged in front of the opening and provided with the first orifice; and a second outer part, arranged in front of the sealing part and comprising a second orifice, being able to rotate with respect to the first outer part so as to give as necessary a superposition of variable surface area, or an absence of superposition, of the second orifice over the first orifice.

A rotation on the second outer part of the plug makes it possible to open it to the desired degree, whereas, since the first outer part of the plug is rotating with respect to the container, this may be rotated to assist the mixing of the contents and the flow of same. The use of simple means of rotation between the container and the parts of the plug enables easy handling, even by rudimentary devices; and the movement, assisting the mixing of the contents of same, of the container may be accomplished continuously throughout the dosing.

The plug may further comprise a connection part, assembled to the container around the opening, having a passage traversing it and leading to the exterior, and also having the connection. With such a construction, the plug is easily removable and may be replaced by a conventional complete sealing plug, which properly confines the product in the container, outside of dosing periods.

The connection part may be assembled to the container by an adjustment of concentric smooth parts, by a screw down nut and a locknut, the screw down nut being borne by one of the container and of the connection part so as to be able to rotate freely, the screw down nut and the locknut being screwed onto a thread established on the other of the container and of the connection part.

This arrangement is very reliable for preventing accidental unscrewings, while again using a rotating movement to realise the assembly or the separation.

It also advantageous that the first outer part comprises a stem extending into the container through the opening, in order, here as well, to accentuate the movement or the mixing of the product.

The connection part is advantageously provided with a circular collar, and the first outer part then comprises an assemblage of two parts clasping together the collar; similarly, the first outer part advantageously comprises a second circular collar, and the second outer part comprises an assemblage of two parts clasping together the second collar. In such constructions, particularly if the assembled parts are screwed down in an adjustable manner and optionally blocked by a locknut, the clearance between these assembled parts and the collars may be adjusted to a quite low value to reduce to almost nothing the amount of product that can interfere therewith through dissemination. This makes it possible to limit the retention, that is to say the amount of powder present inside the mechanism of the dosing system when the container has been emptied.

Another aspect of the invention is a dosing assembly comprising the preceding dosing device, as well as a machine comprising a raising frame itself comprising a support traversed by a vertical boring, the dosing device comprising reliefs resting on the support around the boring, the boring then containing the plug, and the machine further comprises a system for immobilising the plug and a system for rotating the container. And, advantageously, the plug and the boring have first mutually imbricated reliefs which maintain the plug immobilised against rotations; the first reliefs of the plug are placed on the first outer part, the second outer part and a ring delimiting the boring and rotating in the support have second mutually imbricated reliefs that maintain them integral in rotation while enabling the second outer part to rotate with respect to the first outer part; and the dosing device is provided with third reliefs resting on the support around the boring, the plug being flush under the support.

The invention will now be described in its different aspects with reference to the following figures, which represent a purely illustrative illustration thereof:

FIG. 1 schematically shows the dosing method;

FIGS. 2 and 3 illustrate the dosing device;

FIGS. 4 and 5, the end of the dosing device through which the product is distributed;

FIGS. 6 and 7, the machine associated with the dosing device to carry out the dosing;

FIG. 8, a representation of the stirring rod;

and FIG. 9, another view of the machine.

FIG. 1 schematically represents the manner in which the dosing method is carried out. The dosing devices 1 are positioned in a confined enclosure or more generally any place and each comprise a container 2 having an upper opening 3 closed by a plug 4. When the contents of one of the dosing devices 1 has to be dosed, the dosing device 1 is grasped and taken to a machine 5 described in FIGS. 6 and 7, comprising a guide 6, a system for immobilising 7 and a system for rotating 8, both mounted on a support not represented. A receiving recipient 9 positioned on a balance 10 extends under the immobilisation system 7. The dosing device 1 is turned round and installed in the machine 5 so that its plug 4 extends through the immobilisation system 7 and so that its container 2 can be rotated by the system for rotating 8. The plug 4 having been opened in the manner that will be detailed hereafter, the contents of the dosing device 1 flow into the receiving recipient 9 with the desired characteristics.

The plug 4 is represented in FIGS. 2 and 3, in exterior and sectional view. The container 2 is essentially cylindrical, while comprising a peripheral portion 11 established around its outer wall and which comprises flat facets 12, here four, intended for gripping by a remote handling grip 13, and a thread 14 close to the opening of the container 2. The plug 4 comprises three parts, mutually mobile with respect to each other, of which a connection part 15, a first outer part 16 and a second outer part 17. The connection part 15 is traversed right through by a passage 18 opening out into the container 2. Its general form is made of steps and it becomes slimmer outwards from a smooth cylindrical portion 19 for connection to the container 2, engaging with a very small clearance around the end, also smooth, of the wall of the latter which, for its part, is concentric. A nut 20 rotates around the cylindrical portion 19, while being retained axially thereon, particularly in coming against a shoulder 21 leading to the following step. The connection is made when the nut 20 is engaged on the thread 14. A locknut 22 is mobile on the thread 14 in front of the end of the nut 20 and may be tightened onto it, in order to make involuntary untightening impossible. The nut 20 is provided with gripping facets 23 analogous to the facets 12 and used for the transport of the plug 4. It is also provided with capstan stems 24, spread out on its periphery, in order to enable it to rotate easily. The locknut 22 is provided with analogous capstan stems 25. These capstan stems 24 may be dismantleable or non-dismantleable. The surface state of the parts representing the interior volume of the dosing device will be very well cared for, in order to facilitate the flow of the powder.

The end portion of the connection part 15 is a more or less smooth distribution neck 26 but which nevertheless comprises a collar 27 protruding outwards and around which the first outer part 16 of the plug 4 is installed: the first outer part 16 is mainly composed of two assembled portions 28 and 29, established on either side of the collar 27, overlapping it and joined together by a thread 30; this assemblage makes it possible to install the first outer part 16 around the collar 27 with quite a small clearance in order to thwart the interference of impurities and particularly disseminated materials stemming from the loading of the dosing device 1 or from a later loading while enabling the first outer part 16 to rotate around the connection part 15 and an axis coaxial to the passage 18. A locknut 31 is placed on the thread 30, in order, as previously, to immobilise the assembled portions 28 and 29 at the desired position by jamming them. The rotation of the parts with respect to each other is favoured by the presence of bearings 60.

The second outer part 17 similarly comprises two assembled portions 33 and 34, extending on either side of a second collar 35, itself established on the first outer part 16 of the exterior side; the assembled parts 33, 34 are again joined by a thread 36 and held in place by a locknut 37 established on the thread 36. Here again, an adjustment of the axial clearance between the second collar 35 and the assembled parts 33, 34 is sought in order to thwart the ingress of disseminated materials.

FIGS. 4 and 5 will now be commented on. The first outer part 16 comprises a sealing part 38 in front of the output end of the passage 18, provided with a first output orifice 39 of the contents of the dosing device 1. The second outer part 17 comprises a sealing part 40 covering the preceding and provided with a second orifice 41, also of triangular section. The orifices 39 and 41 having similar radii, the rotation of the external parts 16 and 17 on each other makes it possible as necessary to maintain the dosing device perfectly closed, by avoiding a superposition of the orifices 39 and 41, or, on the contrary, to open more or less this dosing device by establishing a superposition of said orifices and by varying the surface area of this superposition.

The plug 4 further comprises a stirring rod 42, integral with the first sealing part 38 and which extends to the inside of the passage 18, while occupying a part only of its section up into the container 2, in order to help the mixing of the powder and the flow of same when the container 2 is rotated. The stirring rod 42 (FIG. 8) has a semi-circular section and convexity adjacent to the edge of the passage 18, but the end of which, situated in the container 2, has a hollowing out 43 dividing the stirring rod 42 into two parallel branches 44. Several lugs 45 are arranged along the stirring rod 42. These arrangements make it possible to facilitate the mixing of the powder. Another lug 45 fixes the stirring rod 42 to the sealing part 40.

This dosing device is not used alone in principle, but in cooperation with the machine 5 to form a dosing assembly, the description of which will now be described by means of FIGS. 6 and 7.

The dosing device 1 is turned round and positioned on a support 46 protruding from one side of a frame 47 of the machine 5. The receiving recipient 9 and the balance 10 on which it is positioned are situated under the support 46. The system for rotating 8 comprises a motor 48 mounted on the frame 47, a transmission 49, and a plate 50 rotating in the support 46 around a vertical axis and on which the nut 20 engaged around the cylindrical portion 19 of the part 15 for connecting to the container 2 is positioned. The transmission may consist of a belt stretched between two pulleys, one of which depends on the output shaft of the motor 48 and the other on the plate 50. It is thus possible to make the container 2 and the connection part 15 continually rotate during dosing. Since the support 46 and 50 is traversed completely by a vertical boring 51, the plug 4 is flush under the support 46 and extends immediately above the receiving recipient 9. The boring 51 is formed more precisely through the plate 50 as well as through a socket 52 and a ring 53 which receive respectively the first outer part 16 and the second outer part 17. The socket 52 is fixed with respect to the support 46, but the ring 53 rotates with respect to it, like the plate 50. Bearings, all referenced 54, connect the support 46 to the plate 50 and to the ring 53, and the socket 52 to the same, and thus enable these rotations. The rotation speed being variable, it is possible to carry out the dosing in several steps:

-   -   maximum opening and speed of rotation up to the approach of the         desired amount of dosed powder (which brings a time saving);     -   reduction of the opening and the speed to obtain the desired         precise amount of dosed powder (which brings a gain in         precision);     -   closing the opening when the set point is reached, stopping the         rotation.

It should be noted that these operations can be fully automated: for this it suffices to replace the stem for adjusting the opening by a second motorisation, commanded by the command-control computer.

The socket 52 comprises a groove 55 receiving a lug 56 of the first outer part 16, and, similarly, the ring 53 comprises a groove 57 receiving a lug of the second outer part 17. Thanks to this arrangement, the first outer part 16 is fixed in rotation and, since the ring 53 is free, it remains normally fixed, but it may be rotated as necessary with the second outer part 17 of the plug 4, in order to adjust according to the needs of opening the dosing device 1. A slug 61 erected on the plate 50 (FIG. 9) receives one of the capstan stems 24 as far as it will go, and guarantees the driving in rotation without slipping of the dosing device 1. A device 62, with graduations and Vernier scale for example, may be added to the ring 53 and the frame 46 to express this opening in an immediately understandable manner. The reference state of the plug 4 is provided by the lugs 56 and 58, cooperating with the grooves 55 and 57; these, like them, are then aligned.

An envisaged application for the invention is the dosing of radioactive powders. The dosing devices 1 are consequently shielded in the embodiment actually represented. Dosings of other powders and products in other fluid states are possible.

The plug 4 is normally sufficient hermetic, which makes it possible to handle and tilt the dosing devices 1 without risk. It may nevertheless be replaced if necessary by another plug, not represented, outside of dosing periods. Such a plug would have a connection part similar to the part 19 of the plug 4 present and a continuous sealing part.

An embodiment has been described here where the plug 4 was metal. A plug made of polymer would not be excluded; its shape would be identical, but the number of parts could be reduced and its structure would thus be simplified thanks to the greater facility of constructing parts of more complex shape by moulding and to the possibility of forming assemblages by ratcheting. 

What is claimed is: 1-13. (canceled)
 14. Dosing device (1) comprising a container (2) having an opening (3), a plug (4) arranged at the opening of the container and having a first orifice, and a mobile mechanism on the first orifice of the plug to open or close as necessary the plug and thus the dosing device; characterized in that the plug comprises: a first outer part (16), arranged around a connection (15) to the container (2), the connection being placed at the opening (3) of the container (2), so as to be able to rotate around said connection, and further comprising a sealing part (38) also arranged in front of the opening and provided with the first orifice (39); and a second outer part (17), arranged in front of the sealing part (39) and comprising a second orifice (41), while being able to rotate with respect to the first outer part so as to give as necessary a superposition of variable surface area, or an absence of superposition, of the second orifice (41) over the first orifice (39).
 15. Dosing device according to claim 14, characterized in that the plug further comprises a connection part (15), assembled to the container (2) around the opening (3), having a passage (18) traversing it and leading into the container, and also having said connection.
 16. Dosing device according to claim 15, characterized in that the connection part is assembled to the container by an adjustment of concentric smooth parts (19), by a screw down nut (20) and a locknut (22), the screw down nut (20) being borne by one of the container (2) and of the connection part (15) so as to be able to rotate freely, and the screw down nut and the locknut being screwed down onto a thread (14) established on the other of the container and of the connection part.
 17. Dosing device according to claim 14, characterized in that the first outer part (16) comprises a stirring rod (42) extending into the container through the opening (3).
 18. Dosing device according to claim 14, characterized in that the connection comprises a circular collar (27), and the first outer part (16) comprises an assemblage of two parts (28, 29) clasping together the collar.
 19. Dosing device according to claim 14, characterized in that the first outer part (16) comprises a second circular collar (35), and the second outer part (17) comprises an assemblage of two parts (33, 34) clasping together the second collar.
 20. Dosing device according to claim 17, characterized in that the stirring rod has a semi-circular section, divided into two branches (44) at one end extending into the container (2), and is provided with projecting lugs (45).
 21. Dosing device according to claim 16, characterized in that the second outer part (17) comprises two assembled portions (33, 34) extending on either side of a second collar (35) established on an exterior side of the first outer part (16), joined by a thread (36) and held in place by a locknut (37) established on the thread (36).
 22. Dosing assembly comprising a dosing device according to claim 14 as well as a machine (5) comprising a raising frame (47) itself comprising a support (46) traversed by a vertical boring (51), the dosing device (1) comprising reliefs (20) resting on the support (46) around the boring (51), the boring (51) then containing the plug, and the machine (5) further comprises a system for immobilizing (7) the plug (4) and a system for rotating (8) the container (2).
 23. Dosing assembly according to claim 22, characterized in that the plug (4) and the boring (51) have mutually imbricated first reliefs (55, 56) which maintain the plug (4) immobilized against rotations.
 24. Dosing assembly according to claim 23, characterized in that the first reliefs of the plug are placed on the first outer part, and in that the second outer part (17) and a ring (53) delimiting the boring (52) and rotating in the support (46) have mutually imbricated second reliefs (57, 58) which maintain them integral in rotation while enabling the second outer part to rotate with respect to the first outer part.
 25. Dosing assembly according to claim 22, characterized in that the dosing device (1) is provided with third reliefs resting on the support (46) around the boring (51), the plug (4) being flush under the support (46).
 26. Dosing assembly according to claim 22, characterized in that the system for rotating (8) the container (2) is a variable speed system. 